IPv6 transition presents many challenges to the Internet community, and various solutions have been proposed, including dual stack, tunneling, and translation. Tunneling supports "like-to-like" IP connectivity across an "unlike" network, whereas translation supports "like-to-unlike" IP interconnectivity. No overarching strategy exists to address all possible scenarios. Because tunneling can keep the end-to-end model that the Internet is built on, the authors have developed a tunnel-based framework that solves the transition problems in backbone and access networks with different tunneling mechanisms.